[TOMT] Teenager kills off friend group off, then frames the other friend.

I’ve been trying to figure out this movie for the longest time to point where I’m beginning to think I’ve made it up. I know it’s a murder mystery and it starts off showing the crime scene of this girl at the school after being murdered. it’s a friend group and one of the guys in the group is the murderer. he pushed one of the friends off a train. also it’s this one weird scene where one of the guys blows up a cockroach then I know for sure at the end of the movie there’s this big reveal that who we thought was the killer isnt and it’s actually the main nice guy character. I remember these being some of the scenes but they could be wrong because I think I was like 8 when I watched them. film could’ve took place 2010- 2016. anyways I need to know if I’m crazy or not! (also could be foreign idk)